Serial adder/substracter utilizing counters

ABSTRACT

The disclosure relates to an electronic desk type calculator wherein a pair of four element counters acting together in conjunction with timing and other circuitry are capable of performing the functions of shifting, addition, subtraction, multiplication and division.



1. An electronic calculator comprising: a. an up counter; b. a down counter; c. memory means; d. reading means associated with said memory means for reading digits out of said memory means; and e. control means controlling said reading means and said up counter, said control means entering a first digit in said memory means into said up counter during a first interval and adding a second digit in said memory means to said first digit in said up counter during a second interval, the lower order sum of said first and second digits being transferred from said up counter to said down counter substantially instantaneously after the termination of said second interval.
 2. A device as recited in claim 1 further including: a. a carry storage device; b. means responsive to a predetermined condition of the lower order sum in said up counter for storing a carry in said carry storage device during said second interval; and c. means for successively entering the carry from said storage device into said up counter after the termination of said second interval.
 2. means for conditioning said borrow counter to represent a count of one each time said second counter passes through its zero state; and
 3. means for entering said count from said borrow counter into said first counter for debiting the next digit representation entered.
 3. A device as recited in claim 1 further including: writing means controlled by said control means for writing the lower order sum in said down counter into said memory means during a third interval.
 4. An electronic device comprising: a. a first counter; b. a second counter; c. a memory means; d. means for entering representation of a digit from said memory means into said first counter; e. means for broadsiding the digit representation from said first counter into said second counter; f. means for entering representation of a digit from said memory means into said second counter to debit the digit representation already there and obtain a difference; and g. means for writing the difference appearing in said second counter into said memory means.
 5. A device as set forth in claim 4 further including: means for resetting said first counter with the concurrence of broadsiding said digit representation into said second counter.
 6. A device as set forth in claim 5 further including: means responsive to a predetermined state of said second counter for debiting the next succeeding digit representation entered into said first counter by one.
 7. A device as set forth in claim 6 wherein said responsive means includes:
 8. An electronic calculating device comprising: a. an up counter; b. a down counter; c. means for conditioning said up counter to represent a digit; d. means for broadsiding the digit representation from said up counter into said down counter; e. means for debiting the digit representation in said down counter; f. a borrow storage device; g. means for successively entering a borrow count from said down counter into said storage device each time said down counter passes through its zero state; h. means for resetting said up counter; and i. means for transferring said borrow count from said borrow storage device into said up counter to debit said up counter by ''''1'''' substantially instantaneously with the resetting thereof. 